Interesting colours on the beetle, I know that some insects have patterns and markings that only show under UV, but the big differences between colours on the beetle here surely suggest that it was doped/contaminated with different materials to make it glow in different colours?

It is a sealed tube right? That glass blower actually put that beetle in-there when making the tube or can you open it up and put samples in, evacuate and fill with gas?

"Interesting colours on the beetle, I know that some insects have patterns and markings that only show under UV, but the big differences between colours on the beetle here surely suggest that it was doped/contaminated with different materials to make it glow in different colours?"

The beetle is an artefact, you see the colours of different fluorescent materials.

"It is a sealed tube right?"

Yes, the tube is more than 100 years old.

"can you open it up and put samples in, evacuate and fill with gas?"

No, but I will try to get a tube which can be evacuated and filled with a gas.